dynamic braking resistors Archives

Ensuring uptime in data centres

ENSURING UPTIME IN DATA CENTRES

HOW RESISTOR SOLUTIONS POWER AND PROTECT DIGITAL NETWORKS

Data centres are the unseen backbone of the digital economy. According to TechUK, they contribute £4.7 billion in Gross Value Added (GVA) to the UK economy every year — a figure that continues to grow alongside demand for cloud computing, AI processing and digital services. But behind the servers and storage units lies a complex electrical infrastructure that must perform seamlessly. Here, Mike Torbitt, managing director of Cressall, explains how resistors help safeguard data centres from costly power disruptions.

The digital transformation of businesses across every sector has placed extreme pressure on data centres. Handling greater volumes of information faster and more efficiently demands increasingly sophisticated infrastructure and additional power. Ensuring this infrastructure runs reliably and without interruption is essential, particularly as outages can result in significant financial losses, data corruption and reputational damage.

KEEPING POWER UNDER CONTROL

One of the biggest challenges data centre operators face is power stability. Voltage fluctuations, whether sudden drops or surges, can severely disrupt sensitive IT equipment such as servers, storage arrays and networking gear, which are all finely tuned to operate within specific voltage ranges. Even small deviations can lead to data corruption, hardware malfunctions or premature wear. Over time, these fluctuations not only drive up maintenance costs but also shorten the lifespan of expensive infrastructure.

Power interruptions, even just momentary losses, can have equally damaging consequences. A brief outage can bring entire systems offline, forcing emergency shutdowns and triggering lengthy reboot sequences. In high-availability environments, where uninterrupted uptime is paramount, even a few seconds of downtime can result in lost transactions, missed service level agreements and compromised services for thousands of users.

Excess energy is another factor that needs to be managed efficiently to prevent overheating and maintain energy efficiency. With data centres under growing scrutiny for their environmental footprint, electrical infrastructure must be designed to support both performance and sustainability.

RESISTOR SOLUTIONS FOR MODERN DATA CENTRES

Resistor technology is vital in supporting the performance, safety and longevity of data centre electrical systems. Neutral earthing resistors (NERS), in particular, are key to maintaining power resilience and operational safety.

NERs are primarily used to limit the current that flows during an earth fault, protecting both personnel and equipment. If a fault occurs, such as a short circuit to ground, NERs restrict the fault current to safe levels, preventing damage to transformers, switchgear and other components. By supporting controlled fault management, NERs help data centres stay operational while faults are safely isolated and resolved. This ultimately contributes to improved system uptime and reduced risk of severe damage.

Another resistor type that supports continuous, reliable power in data centres is dynamic braking resistors (DBRs). These resistors help to regulate power during transitions between power sources, particularly when switching to backup systems such as generators or uninterruptible power supplies (UPS).

Voltage fluctuations during these transitions can damage connected equipment or cause trip events. DBRs mitigate this by absorbing excess electrical energy and convert it into heat, preventing overvoltage conditions and enabling a smoother transition. By controlling power flow, they reduce stress on the system and help avoid unscheduled outages.

Both NERs and DBRs can be tailored to meet the specific demands of data centres, including space constraints, cooling considerations and compliance with international electrical standards. Cressall’s resistor designs also prioritise ease of maintenance, high thermal performance and long operational life — crucial for facilities like data centres that must operate without interruption.

As power demands grow and data centre operators look for ways to expand sustainably, the role of resistors will only become more important. From protecting critical equipment to ensuring compliance with safety standards, resistor technologies such as NERs and DBRs will be crucial in keeping the UK’s digital infrastructure secure, efficient and online.

Cressall has decades of experience in supporting vital electrical infrastructure. To find out how our resistors could benefit your data centre application, get in touch with our team.

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Consistent crane control

CONSISTENT CRANE CONTROL

Crane control using cressall motor control resistors

UNLOCKING EFFICIENT MOTOR CONTROL WITH RESISTORS

Cranes are the backbone of industries like construction, manufacturing and logistics, where the lifting and precise placement of heavy loads are essential. Ensuring that cranes operate smoothly, safely and efficiently requires sophisticated motor control systems. Here, Mike Torbitt, managing director of Cressall Resistors, explains the role that resistors can play in ensuring consistent, efficient crane control.

From erecting skyscrapers and loading cargo at ports to maintaining power plants and assembling aircraft, cranes are crucial for operations that require robust and reliable lifting solutions. As the construction industry continues building upwards — with 600 more skyscrapers in the pipeline for London alone — cranes will be key to realising future industry projects.

A CRUCIAL CONTROL SYSTEM

At the heart of crane operations is a control system, which is responsible for managing the various movements and functions of the crane. These systems include both mechanical controls, like gears and pulleys, and electrical controls, such as motor drives and braking systems. The primary objective of a crane control system is to ensure that the crane operates efficiently and safely — whether that’s lifting a beam into place on a skyscraper or positioning a delicate component in a manufacturing process.

Motor control systems in cranes play a crucial role in managing the speed, torque and direction of the crane’s movements. They enable operators to have precise control over the crane’s actions, from the gentle lifting of a load to the exact positioning of materials.

Advanced control systems also include features for monitoring and adjusting performance in real-time, which helps to maintain the operational efficiency and safety of the crane. By integrating these controls, cranes can achieve higher productivity, reduced operational costs and improved safety.

THE ROLE OF MOTORS

Motors are the powerhouses behind the various functions of a crane, driving the mechanisms that lift, lower and move loads. In crane systems, motors are used to control different parts, including the hoist, trolley and the crane’s overall movement on its tracks or rails. Each motor’s performance must be precisely managed to ensure that the crane can handle heavy loads safely and efficiently. Several advanced motor control technologies are required to provide the necessary regulation and coordination for optimal crane operation.

Variable frequency drives (VFDs) are one critical component in crane motor control systems. They adjust the frequency of the electrical power supplied to the motors, allowing for precise control of motor speed and torque. This is essential for the smooth lifting and lowering of loads, as well as for finetuning the crane’s movements. By optimising motor performance, VFDs help reduce energy consumption and mechanical stress, extending the life of the crane’s components and enhancing overall efficiency.

Dynamic braking systems are another essential, allowing for rapid deceleration and stopping of the crane’s movements. This capability is critical for ensuring safety and preventing accidents, especially in emergency situations where quick response times are necessary. Dynamic braking systems help manage the kinetic energy generated by the crane’s movements, converting it into heat and dissipating it safely, which prevents potential hazards associated with uncontrolled load movement.

RESISTOR RELIABILITY

Resistors play a vital role in a crane’s dynamic braking system, by managing power dissipation and ensuring safe and efficient operations. In crane applications, resistors are used in various ways to enhance the performance and reliability of the control systems.

When a crane slows down or stops, the kinetic energy from the moving parts is converted into electrical energy, which needs to be dissipated to prevent damage or overheating. Resistors absorb this energy and convert it into heat, allowing for controlled and safe deceleration. This is crucial for maintaining the stability and safety of the crane, especially when handling heavy loads or during emergency stops.

Cressall Resistors is a leader in power resistor solutions, offers a range of products specifically designed for crane motor control systems. Its dynamic braking resistors are designed specifically for high-power applications, to operate efficiently in demanding and harsh environments often encountered in crane operations.

Motor control systems are the backbone of efficient, safe crane operations. By integrating these technologies, and the resistors that safeguard the systems, cranes can achieve superior performance, reliability and safety, elevating efficiency across many industries.

CRESSALL MOTOR CONTROL RESISTORS

CRESSALL DYNAMIC BRAKING RESISTORS

Diving into marine resistor design

DIVING INTO MARINE RESISTOR DESIGN

DESIGN CONSIDERATIONS FOR OFFSHORE ELECTRICAL COMPONENTS

Covering over 70 per cent of the Earth’s surface, the oceans are a vital element of our planet’s ecosystem. However, for the millions of vessels that cross them, the aquatic environment can present a problem. Vessels are increasingly using electrical systems to power across oceans, but a component’s design must account for these extreme conditions.

Whether for main propulsion propellors, crane or lifting systems, or cable laying, electrical drives can be found at the heart of many marine operations, offering increased control, reliability and mechanical simplicity. Dynamic braking resistors (DBRs) are an essential part of an electric drive system that remove excess energy from the system when braking to either dissipate as heat if system is not receptive to regeneration or if system is receptive, but energy level goes beyond the system limits, so needs to be removed.

When designing electrical components for offshore applications, material selection is key from the start of the process to guarantee that equipment will perform under harsh conditions, including saline atmosphere, high wind loadings and corrosive sea water.

Engineers tasked with designing resistors for marine applications must consider material choice, structural stability and cooling method.

CORROSION-RESISTANT MATERIALS

Sea water and the saline atmosphere is corrosive, which could leave equipment inoperable. Due to this, stainless steel, combined with special paint systems, is typically used for the enclosure metalwork for resistor elements. With materials containing at least 10.5 per cent chromium, stainless steel reacts with oxygen in the air to produce a protective layer on its surface to prevent corrosion if not painted.

There are many grades of stainless steel that can offer high corrosion resistance, which can be further enhanced by the addition of extra elements. For below-deck applications, 316 and 304 stainless steel contain nickel to broaden the protective layer created by the chromium, and can be used in unpainted condition.

However, for above-deck components, 316 stainless steel has a higher nickel quantity and added molybdenum, so the resistor unit’s metalwork receives optimum protection against the marine atmosphere, but in some conditions, painting will also be required. Cressall’s resistor enclosures for the EV2 resistor terminal cover boast at least an IP56 ingress protection rating, certifying that sea water cannot enter the unit to cause harm.

In addition to the exterior, it is important that the resistor’s element can withstand the harsh conditions. For these applications, Alloy 825 sheathed mineral-insulated elements are less vulnerable to atmospheric corrosion. As the element in encased within the mineral insulated sheathing, the sheath is at earth potential, so if water or high humidity is present this will prevent accidental contact with the live element, making them a much safer choice for marine applications.

STRUCTURAL STABILITY

Weather at sea is unpredictable, so vessels must be able to withstand the large variance in wind and harsh sea conditions found worldwide. Many offshore structures such as wind turbines are located in areas with high winds, so if the system requires resistors to help provide stability to their electrical components these considerations must be considered within a resistor’s design.

Considering the impact of a vessel’s rotational motions — its side-to-side motion, or pitch, and its front-to-back motion, or roll, is crucial. Design engineers need to ensure that there is enough mechanical support in the structure to stabilise the resistors for safe operation when it is subjected to these forces.

Cressall can conduct finite element analysis (FEA) to help ensure structural stability. FEA allows design engineers to predict a product’s performance in the real world, then see the impact of forces and make changes accordingly. This ensures the resistor performs well in the potentially extreme weather conditions.

It’s also important to consider the size constraints of marine applications. In contrast to onshore units, offshore electrical components must fit into a compact area, so the size of the unit’s support structures must be minimised without compromising durability.

COOLING METHOD

An essential part of a resistor is its cooling system. Since the resistor dissipates excess energy as heat, the cooling system is responsible for cooling the resistor element to ensure continued operation. Depending on the layout and resources of the system, resistors can be naturally or forced air or water-cooled.

Air-cooled resistors come in two types — forced and naturally cooled systems. Forced cooling systems use a fan to dissipate heat in a compact space. These units are suitable for deck mounting and can be secured using anti-vibration mounts. Natural cooling is the most common in marine applications, offering a higher power rating and can be mounted in machinery spaces, protected environments or on deck. For machinery spaces or protected areas, consideration should be given to how the hot air released from the resistors should be evacuated to ensure other equipment mounted locally does not overheat.

Alternatively, the cooling system can use the vessel’s chilled water system, which circulates cool water for air conditioning and equipment cooling. If the chilled system uses sea water, titanium-sheathed elements with super duplex steel metalwork can be incorporated, for continuous use in acidic, tropical sea water and downgraded to 316 stainless steel for freshwater systems.

The ocean is a valuable asset for energy, transport and trade. Ongoing development of electric drives for marine applications can be challenging, but taking these conditions and energy savings into account makes them a viable and advantageous option for powering vessel and for use in offshore structures.

When required Cressall can design the resistors to help with your application. Contact us here.

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Industry the planet’s close friend

INDUSTRY: THE PLANET’S CLOSEST FRIEND OR MOST SWORN ENEMY?

REALISING THE GOVERNMENT’S BUILD BACK BETTER PLAN

Britain — the birthplace of the Industrial Revolution, the golden age of innovation that transformed society. However, the fossil fuels that powered the revolution have left a detrimental mark on our world, which we are fighting to change with Net Zero. Is the industry that triggered the climate crisis in the first place part of its solution?

The Industrial Revolution transformed the world, igniting technological development that continues to this day. But it has also had disastrous consequences for the planet, with carbon emissions from fossil fuel use triggering the climate crisis.

However, the necessity of industry is well recognised. The UK’s manufacturing and refining sectors contribute £180 billion to the economy and provide millions of jobs, both directly and indirectly across the entire manufacturing value chain, presenting a dilemma — is industry a help or a hindrance to the planet’s future?

INDUSTRY’S CARBON CONTRIBUTIONS

The Industrial Revolution triggered a rise in the Earth’s core temperature that is yet to stabilise. Since 2018, the Intergovernmental Panel on Climate Change (IPCC) has been warning us that a temperature increase of more than 1.5 degrees Celsius (°C) above pre-industrial levels will result in irreparable damage from extreme weather, failed harvests and species extinction.

The Government’s Net Zero strategy provides a roadmap to successfully combatting the climate crisis. Published in October 2021, Build Back Better gives details on how the UK will achieve Net Zero carbon emissions by 2050. Industry is at the heart of this challenge, both as a carbon contributor and emission eliminator.

Industry is a major source of carbon emissions, producing 15 per cent of the UK’s total. The Government estimates that emissions associated with industry need to drop by as much as 96 per cent by 2050 to achieve Net Zero status — demonstrating the magnitude of its current contribution to the climate crisis.

RESOLVING INDUSTRY’S PROBLEM

Industry’s damage to the planet has incrementally decreased over the last couple of decades. However, to keep momentum, further innovation is necessary to reach Net Zero in this huge carbon-emitting sector, both directly and indirectly.

According to the International Energy Agency (IEA), industry’s indirect carbon contribution through its colossal energy consumption accounts for 40 per cent of the globe’s total. The move to a decarbonised renewable power supply will help eliminate this.

However, the situation is more severe with direct CO2 industrial emissions. Since some crucial processes don’t currently have a carbon-free alternative, emission elimination is not always possible — reduction is as far as it can go. CCS is key to aligning industry with Net Zero, ensuring essential carbon-emitting processes continue without the climate consequences.

INDUSTRY’S INNOVATIVE INPUT

Despite being responsible for a large proportion of emissions and acting as a catalyst for the birth of the climate crisis, industry is also the planet’s saving grace.

The Government’s Net Zero strategy is striving for a fully decarbonised, reliable power supply that integrates both renewable sources, like solar and wind, and dispatchable net-zero sources like natural gas with carbon capture and storage (CCS). In transportation, the goal is to ensure all cars are zero-emission capable by 2035, end the sale of petrol and diesel heavy goods vehicles (HGVs) by 2040 and achieve a net-zero rail network by 2050.

Reaching these challenging targets involves key manufacturers developing innovative products and services to enable Net Zero. For example, at Cressall Resistors, we manufacture a range of resistors crucial to reaching Net Zero. For the automotive market, the EV2 dynamic braking resistor facilitates regenerative braking in electric vehicles, helping to increase vehicle range and improve the viability of a fully electric national fleet at an unrivalled weight and size to power ratio.

When it comes to decarbonising the nation’s power supply, pre-insertion resistors are used to prevent overvoltages caused by renewable energy’s variable input, while load banks safeguard all power systems by proving their power generation capability. Resistors are necessary to protect every electrical system and make Net Zero a realistic goal.

The Industrial Revolution is by and large to blame for the catastrophic levels of CO2 that have been emitted into our atmosphere since the eighteenth century. But it’s also a crucial part of the solution. Not only through eliminating its own carbon footprint, but also by developing the components to decarbonise other sectors.

With the full Net Zero strategy revealed, now’s the time for industry to step up and take responsibility for preventing more damage to the planet and shift its position from the planet’s most sworn enemy to its closest friend.

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